I also use one of those driveway motion sensor sends beep to remote. Wakes u up if dozing off.
Got mine from Harbor Freight for $10, one of the best investments I've made. Last 3 hogs I killed were because of this thing. I can now work on the place all day, sleep at night, and "hunt" at the same time. Just last Thursday night I was awoken at 10:30, shot a sow, put hams and back-strap on ice and was back in bed at 11:30.